He consistently has been one of the best third basemen in baseball for most of his career -- as selected by a group of experts that includes Peter Gammons and statistical pioneer Bill James.

If you go a little deeper into John Dewan's plus-minus scale, the primary metric used by the Fielding Bible, it reveals that Beltre's side-to-side range is the best in the game. For pitchers like Jon Lester who were burned so often last season by ground balls sneaking through the infield, Beltre's side-to-side range will be a tremendous boost next season.

Even in his prime, though, Lowell wasn't the defensive player Beltre is. Consider Lowell during a 2007 season in which he was perfectly healthy from start to finish:To his right: plus-6To his left: minus-6

Even when he was healthy, Lowell was making fewer plays to his left -- to the shortstop side of third base -- than the average third baseman, and he wasn't making up for it with any kind of elite defense to his right.

Compare that to the five best defensive third baseman -- as ranked by Dewan's scale -- in baseball last season:

Chone Figgins, plus-40To his right: plus-1To his left: plus-23

Ryan Zimmerman, plus-28To his right: minus-3To his left: plus-25

Adrian Beltre, plus-27To his right: plus-9To his left: plus-11

Scott Rolen, plus-22To his right: plus-7To his left: plus-8

Evan Longoria, plus-21To his right: plus-3To his left: plus-10

Notice anything?

No third baseman on that list is as balanced as Beltre. Figgins, Longoria and Zimmerman all were better to their left last season than Beltre -- but no one in that group was as good going to their right as Beltre was. No third baseman in baseball, in fact, is better down the line than Beltre.

Theo Epstein made a point of upgrading his infield defense -- and its side-to-side range in particular. Alex Gonzalez, for example, still had the same sure hands he'd always had, but injuries had diminished his range going to his left or to his right.

No third baseman in baseball has better side-to-side range than Beltre.